Biomedical subjects
Publications and source records attributed to C R Jackson.
Three different gels (Sepharose 4B, Sephadex G-200, and Sephadex G-50) were evaluated as a means of removing humic contaminants from DNA extracts of environmental samples. Sepharose 4B gave superior separation of DNA from humics, and DNA purified in this way showed consistently greater amplification than DNA purified by the other materials.
An in vitro dye leakage study was performed to compare the apical microleakage of a glass ionomer root canal sealer to Roth's 801 sealer. Forty-five single-rooted teeth were randomly divided into three groups: Ketac-Endo, Roth's 801, and the control group (no sealer). All groups were instrumented using a step-back technique and obturated with laterally condensed gutta-percha. The teeth were placed in a vacuum chamber under a pressure of 710 torr for 15 min and then immersed in India ink under vacuum for 24 h. The teeth were allowed to passively stain for 4 days and were cleared and evaluated for linear dye leakage using a binocular dissecting microscope. Statistical analysis revealed that sealer significantly improves the apical seal of laterally condensed gutta-percha. However, the apical seal exhibited by Ketac-Endo was not significantly different from that provided by Roth's 801 sealer.
An in vitro dye leakage study was performed to determine the incidence of patent furcal accessory canals following exposure of the pulp chamber to 5.25% sodium hypochlorite. One hundred extracted molars were labeled, endodontically opened, and irrigated for 1 h at 5-min intervals. The external furcations were exposed to 0.5% basic fuchsin for 24 h. Patency was determined by dye presence on the chamber floor. Statistical analysis revealed that first and second molars, regardless of arch position or location, demonstrated a patent accessory canal at a rate of 57% +/- 19.6% in the furcal area. It was concluded that accessory canal exposure to 5.25% sodium hypochlorite in the furcal area of molars produced patency which was demonstrable via passive methods--no vacuum or injection pressures were utilized.
The literature demonstrates that each of the elements of crown fabrication involves possible and probable insult to the pulpal tissues of the tooth. Preparation of the tooth can result in pulpal inflammation or even burn lesions. The impression technique can result in reduction of the odontoblastic layer caused by drying of the dentin. Temporary coverage of the preparation involves the use of self-curing resins and temporary cements, both of which can irritate the pulp. The final restoration is attached with cements that are often implicated in pulpal irritation. Dental caries and the procedures necessary to remove it and restore the tooth before preparation for a fixed prosthesis can injure the pulp. This study was done to evaluate the effects of complete coverage fixed prosthetic restorations on the dental pulp. A recall letter was mailed to 1221 patients who had received a fixed partial denture or single crown during the years 1984-1988. One hundred thirty patients were examined. Each tooth was evaluated for pulpal health, periodontal integrity, and clinical acceptability of the restoration. Of the 603 teeth examined, 166 had undergone root canal therapy before placement of the restoration, leaving 437 that were crowned while vital. Of these, 25 (5.7%) were in need of root canal therapy or had undergone root canal therapy after cementation of the fixed prosthesis.
Inadequate isolation will greatly compromise routine endodontic therapy. Loss of coronal tooth structure to caries or trauma often makes adequate rubber dam isolation difficult to achieve. This article presents some techniques for placing a buildup prior to endodontic therapy. The few minutes spent placing a buildup prior to the initiation of root canal therapy are an excellent investment in time. The time spent will be repaid by the ease of placement of the rubber dam, the quality of isolation achieved, the reduced chance of losing the provisional restoration, and the increased quality of the completed endodontic treatment.
A community hemoccult screening project for colorectal cancer resulted in the processing of 18,198 specimens. Positive test results were reported in 3 percent of the total, which ultimately resulted in the identification of 20 colorectal malignancies (0.1 percent) and 53 benign polyps (0.3 percent). The number of malignancies and polyps identified was disappointingly low. Our findings would challenge the concept of unsupervised mass screening from the viewpoint of cost-effectiveness; however, because of the numerous voluntary services and supplies, this particular project was useful in educating the public about early colon cancer detection.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
During routine endodontic therapy, sodium hypochlorite inadvertently was forced out the apex of tooth No. 12. The patient experienced immediate severe pain, swelling, and hemorrhage from the canal access. Treatment was palliative, including patient education and reassurance, narcotic analgesics, cold and hot compresses, and multiple follow-up visits.